Combined use of sheep manure and di-ammonium phosphate mitigates adverse effects of nitrogen and phosphorus deficiencies and enhance growth, photosynthesis, and yield of soybean under Parwan agro-climatic conditions

Abstract

Severe climate changes in arid and semi-arid regions, for example rising summer temperatures, lowering winter temperatures, and a lack of rainfall, have made calcareous soils' fertility concerns, more specifically nitrogen and phosphorus deficits, progressively worse. Moreover, there is limited information available regarding how sheep manure (SM) and di ammonium phosphate (DAP) affect soybean growth, photosynthesis, and yield, particularly under calcareous soil conditions. This study investigated the effects of sole and combined application of SM and DAP fertilizer namely FT1 (SM = 0%, DAP= 0%), FT2 (SM= 100%, DAP= 0%), FT3 (SM = 0%, DAP= 100%), FT4 (SM = 50%, DAP= 75%), FT5 (SM = 50%, DAP= 50%), and FT6 (SM = 50%, DAP= 0%) on growth, photosynthesis, and yield parameters of soybean cultivar (LD 04-13265 USD) in calcareous soil of a semiarid region in Parwan, Afghanistan. The results indicated that plant height and nodule number were unaffected by fertilization treatments, however growth features including leaf number, root length, and shoot biomass affected significantly. The net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency percentage were found to be significantly higher in FT4 and FT5, compared to FT1 (control). Conversely, each fertilization had a lower intercellular CO2 concentration than FT1. As a result, combined application of SM and DAP fertilizations such as FT4 and FT5 revealed better growth performance, higher photosynthesis efficiency as well as producing more seed yield compared to sole fertilizations. The increased growth, efficient photosynthesis and higher seed yield could be attributed to some extent to support nutrient availability, soil fertility, balanced nutrition, and a favourable soil environment by incorporating SM and DAP fertilizer. Ongoing studies can investigate the long-term effects of combining SM and DAP fertilizer on soil health parameters in calcareous soils. This can include assessing changes in soil pH, organic matter content, microbial activity, and nutrient cycling processes. Understanding these dynamics will contribute to sustainable agricultural practices and long-term soil fertility improvement.